The Oxford Classical Dictionary (ISBN 0198606419) states the following for Feriae, listed under "Festivals, Roman"

The basic notion included not only the hounouring of the gods, but also restrictions on public life: the courts were closed, some agricultural work was restricted, and in some cases holidays given to other workers.

The word feriae applied to specific days, and in its narrowest sense meant simply 'festival' or 'holiday'. Thus, it is seen in general use in the name of a given festival, to simply mean 'festival to'.

Feriae were of three types:

feriae stativae, which were held on a fixed date, held annually;

feriae conceptivae, which were held on a date determined by various officials, also held annually; and

feriae imperativae, which were decreed by the Senate or various other bodies of the State, and held at the decreed date.

Most feriae were also included in the various Fasti, which have been found in homes, inside and outside temples, and in other places in public view.